C++ final Specifier

Last Updated : 7 Jul, 2026

The final specifier was introduced in C++11 to prevent further modification of class hierarchies. It can be used to stop a virtual function from being overridden or to prevent a class from being inherited.

  • final can be applied to virtual functions and classes.
  • It helps enforce design constraints and improves code safety.

Syntax of final

The final specifier can be used in the following ways:

virtual return_type function_name() final;
or
class ClassName final {
// class members
};

Using final with Virtual Functions

The final specifier can be applied to a virtual function to prevent derived classes from overriding it.

CPP 
#include <iostream>
using namespace std;

class Base
{
public:
    virtual void myfun() final
    {
        cout << "myfun() in Base";
    }
};
class Derived : public Base
{
    void myfun()
    {
        cout << "myfun() in Derived\n";
    }
};

int main()
{
    Derived d;
    Base &b = d;
    b.myfun();
    return 0;
}

Output

prog.cpp:14:10: error: virtual function ‘virtual void Derived::myfun()’
     void myfun()
          ^
prog.cpp:7:18: error: overriding final function ‘virtual void Base::myfun()’
     virtual void myfun() final

Explanation

  • myfun() is declared as a virtual function in the base class.
  • The final specifier prevents any derived class from overriding it.
  • The compiler generates an error when Derived attempts to redefine myfun().

Note: The final specifier can only be used with virtual functions.

Using final with Classes

The final specifier can also be used to prevent a class or structure from being inherited.

CPP 
#include <iostream>
class Base final
{
};

class Derived : public Base
{
};

int main()
{
    Derived d;
    return 0;
}

Output

error: cannot derive from ‘final’ base ‘Base’ in derived type ‘Derived’
 class Derived : public Base

Explanation

  • The class Base is declared as final.
  • Since Base cannot be inherited, the compiler reports an error when Derived attempts to inherit from it.

Advantages of Using final

The final specifier provides several benefits:

  • Prevents derived classes from accidentally overriding important virtual functions.
  • Restricts inheritance when extending a class is not desirable.
  • Helps enforce object-oriented design constraints at compile time.
  • Improves code readability, maintainability, and program safety.

Limitations of final

The final specifier also has some limitations:

  • It can only be applied to virtual functions and classes.
  • Classes marked as final cannot be used as base classes.
  • Unlike Java, it cannot be used to create immutable variables or constants.
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